Flaked Lithics

All flaked lithic specimens should be placed directly into ziplock/whirl-pak bags with minimal handling.
Please do not spit, lick, or rub on the artifacts as this may result in positive results for human proteins.
Label the outside of the bag and if desired, place a second label inside the bag.

Control Samples

Since false positives may result from bacteria, animal feces, lippoproteins, and alkaline substances
in the soil, it is necessary to test soil samples with the artifacts. Collect approximately 1 gram samples
from soil surrounding the artifacts and place in suitable containers (film canisters work nicely).
Other control samples:

Control samples will be processed at our discretion and at no additional cost.

This category includes manos, mortars, pestles, etc. We prefer that groundstone and pecked
stone artifacts be sent to our laboratory for extraction, especially if pollen and/or phytolith
analyses are also requested. We will collect a protein residue sample from one side or area
of the groundstone and pollen/starch and/or phytolith samples from a separate area of the
ground surface. Starch granules represent starchy foods such as seeds and roots/tubers
that often are ground in preparation for cooking.

Extracts for protein residue analysis from large metates or bedrock mortars should be
collected by the archaeologist in the lab or field using the methods on page 4.

Ceramics can also be tested for protein residue, pollen, starch, and/or phytoliths.
Whole pots or sherds can be sent for analysis and will be treated in a similar manner
as groundstone. Protein residue analysis cannot be used on carbonized materials as
the protein proteins are too severely denatured to yield results. Ceramics containing visible
residue are excellent candidates for phytolith analysis using a new technique that can
distinguish phytoliths of wild grasses from those of Zea mays and also can identify
variety of maize.

Soils from suspected processing areas and/or kill sites frequently retain the blood
of the animal(s) processed. These soils can also be tested. Small (1 gram) amounts
of the soil(s) to be tested should be placed in a ziplock/whirl-pak bag or clean film
canister and sent for analysis.

Curated artifacts are also possible candidates for protein residue analysis. If the
curated artifacts are stored in trays, they should be placed in separate, labeled
ziplock/whirl-pak bags. If these artifacts are stored in other types of bags, such as
brown paper, please send them in "as is."

ARTIFACT SELECTION/RESEARCH QUESTIONS

 For very large collections of lithics, selection of artifacts sent for protein residue analysis
should fit the research design. Some examples:

If artifacts were multi-purpose tools, it is sometimes possible to identify more than one
type of protein residue, unless the animals are closely related such as sheep and goats,
or deer and elk.

Different types of protein residue may be detected from the hafting area and from the tip
of the same tool. Identification of proteins from the hafting area may identify the hafting
medium. When sending artifacts for hafting area AND tip analysis, please indicate that
each area is to be tested separately. These areas are considered to be two separate
samples and will be charged as two samples.

Protein residue analysis can be used in evaluating different aspects of prehistory.
Examples in which it may be of benefit are:

1. As an objective test of tool function

2. As a test to determine whether animals represented in faunal remains were
processed at the site. 

3. To determine a possible range of animal resources exploited.

Our reports are interpretive, rather than providing just a list of positive reactions.
We identify possible animals represented by positive results based on known
distributions of the animals and known and tested reactions of the antisera.

Artifacts sent for analysis can be tested against the following antisera:

Protein residue analysis has been successfully applied to archaeological materials
from a variety of areas including Arizona, California, Colorado, Idaho, Montana,
Nevada, New Jersey, New Mexico, Pennsylvania, and Texas.

COLLECTING PROTEIN RESIDUE SAMPLES FROM GROUNDSTONE 

Extraction of protein residues is usually performed with a 0.2 M Tris hydrochloride,
0.5 M sodium chloride, and 0.5 % Triton X-100 solution (most desirable), although
a 5 % ammonium hydroxide solution (less desirable) also can be used. The components
for these solutions can be purchased from Fisher Scientific and from Sigma Chemical
Company. When washing groundstone, use as little solution as possible (1-5 mL).
For an additional $10.00 charge, we can use a Centriprep-10 centrifugal concentrator
with a 10,000 molecular weight cut-off membrane. This allows us to concentrate the
proteins in a large volume of liquid down to a sample about 1-2 mL in size. If you opt
to use the Centriprep device, a larger volume of solution may be used to wash the
artifact (up to 50 mL).

Using a sterile (new) toothbrush, vigorously scrub the surface of the groundstone where
a small amount of solution was applied. Decant the liquid using a pipette or syringe and
repeat until a small area of the ground surface has been cleaned. Use additional solution
from the pipette or syringe to "wash" the bristles of the toothbrush to get the residue out of it 

The decanted solution should be placed in a clean (preferably new) screw-capped plastic
container with a tight seal. This container should be placed in a labelled ziplock/whirl-pak bag.
If you have groundstone that was buried in the soil, be sure to scrape off the excess soil and
include a soil control from the same area as the groundstone (preferably not what was
scraped off the tool). Soils commonly contain compounds such as bacteria, lippoproteins,
and animal feces that can cause false positive results for buried artifacts. A 1-2 gram soil
control size is all that is required, and these soil controls are run at no extra charge.

DO THIS PROCEDURE FIRST, BEFORE WASHING THE REMAINDER OF THE SURFACE
FOR POLLEN/PHYTOLITHS/STARCH.

DO NOT USE GLASS CONTAINERS FOR STORING PROTEIN RESIDUES, AS THE
PROTEIN WILL ADHERE TO THE GLASS, MAKING RECOVERY DIFFICULT OR IMPOSSIBLE.